Abstract Angela Castanieto is a strong candidate for the NIGMS Diversity Supplements Program. She is an Hispanic-American graduate student in the UCSF Tetrad PhD program and has already demonstrated an outstanding aptitude for scientific research. In addition, she is very involved with the UCSF community at large and specifically within the Hispanic community at UCSF as a founding member of the UCSF SACNAS chapter. This provides her with the opportunity to interact with people from diverse backgrounds, both as a mentee and a role model. Although Ms. Castanieto is currently in her third year of graduate school, and thus further into her program than the typical candidate for the Diversity Supplements Program, extenuating circumstances have delayed her progress. She arrived at UCSF through a non-traditional path that left her with less experience and preparation in biology than her peers. As a result, she had to retake two of her major first year courses in her second year, and postpone her TA duties until her third year. Unlike her classmates, who started working on their research full-time over a year ago, Ms. Castanieto just completed the last of her nonresearch requirements in December, 2011. Nonetheless, during her short time in the lab, she has obtained compelling preliminary data that suggest a novel mechanism for the regulation of the epithelial stem cell fate in the Drosophila ovary. A one-year supplement would provide Ms. Castanieto with the means to develop her project to the point where she would be competitive for independent support, through mechanisms such as an F31 predoctoral fellowship. Thus, we are requesting a supplement for my R01, titled Modeling epithelial stem cell competition in a dynamic Drosophila ovarian niche, Grant number 5R01GM097158-02.